Sensitization of silver halide emulsions with macrocyclic compounds



United States Patent Ofilice 3,062,646 Patented Nov. 6, 1962 This invention relates to photographic silver halide emulsions, andmore particularly, to an improved means for sensitizing such photographic silver halide emulsions.

A number of methods have been previously described for increasing the sensitivity of photographic silver halide emulsions, other than methods of optical or spectral sensitization, which involve the incorporation of certain colored compounds or dyes in the emulsions. The incorporation of suchdyes in the emulsions increases the optical range of sensitivity, and for this reason such dyes are commonly referred to as optical or spectral sensitizing dyes. It is also well known to increase the sensitivity ofphotographic emulsions by addition of sulfur compounds capable of reacting with silver salts to form silver sulfide, or with reducing agents (compounds of these types are also naturally present in gelatin), or with salts of gold or other noble metals, or with combinations of two or more of the aforementioned compounds generally known as chemical sensitizers. Such chemical sensitizers are believed to react with the silver halide to form, on the surface'of the silverhalide, minute amounts of silver sulfide or of:silver or other noble metals, and these processes are capable of increasing the sensitivity of developing-out emulsions by very large factors. The process of chemical sensitization, however, reaches a definite limit beyond which further-addition of sensitizer, or of further digestion with the sensitizer present, merely increases the fog of the photographic emulsion with constant or decreasing speed.

We have now found a means of further increasing the senstivity of photographic emulsions which may be applied even though the ordinary processes of chemical sensitization have been carried to the eifective limit of the photographic emulsion in question. Our process is to be distinguished from hypersensitization, which is produced by bathing a finished coating with water or with solutions of ammonia, amines or silver salts. Such processes act primarily on optically sensitized photographic emulsions and tend to increase the free silver ion concentration of the emulsion and greatly diminish its stability. Our process is also to be distinguished from hypersensitization by mercury vapor, which gives a transistory effect whichis lost on storage of the 'film. The compounds used in our invention do not appear to be chemical sensitizers in the usual sense, since they increase speed by their presence during exposure and processing and require no digestion with the photographic emulsion to produce the increase in speed, nor does their chemistry indicate that they are likely to react with silver halide under normal emulsion conditions.

The novel'sensitizers of our invention are quite unique in that the effects produced are additive in photographic emulsions which have already been sensitized to their optimum, or near-optimum, with conventional chemical sensitizers, such as labile sulfur compounds. The novel sensitizers of our invention, however, can be used to sensitize photographic silver halide emulsions containing no other sensitizers, if desired. The novel sensitizers of our invention are not strictly chemical sensitizers, since chemical sensitizers do not generally provide the additive effects of the type mentioned.

It is, therefore, an object of our invention to provide photographic silver halide emulsions which have been .at least twelveatoms inthe cycloalkane ring.

sensitized with various macrocycliccompounds containing at least one sulfur atom. Another object of our invention is to increase the sensitivity of ordinary photographic silver halide emulsions which have already been sensitized with chemical sensitizers, such 'as *gold compounds and/ or compounds .containing labile sulfur atoms.

Other objects will become apparent from a consideration of the following'description and examples.

According to our invention, We have found that the sensitivity of an ordinary photographic silver halide emulsion can be materially increased byincorporating therein a macrocyclic compound containing at least twelve atoms in the ring. At least eight of these atoms'in the ringare carbon atoms andat least one of these atoms is a sulfur atom. Themacrocyclic compounds of our'invention also contain at least one oxygen atom and/or one nitrogen atom in the heterocyclic ring. The macrocyclic compounds of our invention can contain various functional groups as substituents-to the macrocyclic ring, or they can actually contain these functional groups within the heterocyclic, macrocyclic ring. Typical functional groups include carboxylicester linkages, carboxylicamide linkages, thioether linkages, ether linkages, etc. Polar functional groups have been foundto provide especially useful results in our macrocyclic compounds.

The macrocyclic compounds of our invention should have sufficient dispersibility in water (or a dilute alkaline solution), or in an organic solvent, such as acetone, the lower aliphatic alcohols (e.g., ethanol, propanol,'butano1, etc.), 1,4-dioxane, ethylacetate, etc. (directly, .or in a colloid mill, or by other means, such as by a dispersing agent, e.g., sodium laurylsulfate, etc.), so that a sensitizing amount of the macrocycliccompound can be adsorbed by or associated with the silver halidegrains.

The macrocyclic compounds useful in practicing our invention can be called thiacycloalkanes, .which contain In general, we have found that particularly useful compounds contain from about eight to sixteen carbon atoms .in the .macrocyclic ring, from about one to .foursulfur atoms wherein-R and "R each represents a hydrocarbon alkylene 'group or an alkylene group, the carbon chain'of'which is interrupted by an oxygen atom, a sulfur atom, a carboxylic ester linkage, a carbonic ester linkage, or a carboxylic amide linkage, and Q represents an oxygen atom or a sulfur atom, provided, of course, that said macrocyclic compound contains at 'least twelve carbon atoms in the marocyclic ring and contains at least one oxygen atom and/ or onenitrogen atom.

Macrocyclic compounds embraced by Formula Iabove, which can be used in our invention, comprise compounds selected from the class'representedby the following general formula:

wherein R and R" each represents an alkylene group, such as ethylene, methyl-substituted ethylene, ethyl-substituted ethylene, propylene, butylene, etc., Q represents -a I and la above can be prepared according to techniques which have been previously described in the prior art. For example. these compounds can be prepared by heating together an alkali metal sulfide (e.g., potassium sulfide, sodium sulfide, etc.) with a compound selected from those represented by the following general formula: hal-Rhal wherein hal represents a halogen atom, such as chclorine or bromine, and R has the values given above. The reaction of one molecule of a compound of Formula II with one molecule of an alkali metal sulfide produces the compounds of Formula Ia wherein Q is an oxygen atom. The reaction of two molecules of a compound of Formula II with two molecules of an alkali metal sulfide produces the compound of Formula Ia Where Q represents a sulfur atom. These condensations can advantageously be carried out in a reaction medium containing substantial quantities of diluent, which favors the formation of macrocyclic compounds. Typical diluents include the lower aliphatic alcohols, such as ethyl alcohol, propyl alcohol, etc., which may or may not be diluted with water. The desired macrocyclic compounds can be readily extracted from the reaction mixture with a suitable solvent, such as one of the lower aliphatic alcohols.

Alternatively, the compounds of Formula I above can be prepared by reacting together one molecule of a compound of Formula II with one molecule of a dimercaptan selected from those represented by the following general formula:

following general formula:

SRz-C&H Y X \SR2-CNE wherein R represents an alkylene group, such as ethylene, methylene, propylene, etc., X represents a hydrocarbon alkylene group, such as ethylene, propylene, butylene, etc., an alkylene group, the carbon chain of which is interrupted by an oxygen atom or a sulfur atom, or the group:

wherein R represents a hydrogen atom, a hydroxyl group, a sulfo group, a carboxyl group, or an amino group, and Y represents a hydrocarbon alkylene group, such as methylene, ethylene, propylene, butylene, etc., or an alkylene group, the carbon chain of which is interrupted by an oxygen atom or a sulfur atom.

The carbon atoms in the macrocyclic compounds of our invention can contain various substituents, such as alkyl groups, aryl groups, substituted alkyl groups, such as carboxymethyl hydroxymethyl, etc.

The compounds of Formula IV above can be prepared according to various methods, which can be summarized as follows:

4 (1) A bis mercaptan added to a N,N'-methylene bis acrylamide type compound.

(2) A bis mercaptan and a his halo methylene amide type reacting in the presence of an acid-binding group.

(3) A bis halide and a his mercapto methylene amide type reacting in the presence of an acid-binding group.

(4) The reaction of a his mercaptan with acrylamide followed by reaction with an aldehyde or ketone.

Alternatively, certain of'the compounds represented 'by Formula IV above can be prepared by conventional methods, such as by acylation of an amine by a carboxylic acid, anhydride, or halide. This method of preparation -is illustrated in one of the following examples. These "compounds can also be prepared by reacting a dibasic acid or halide (or anhydride) with an aliphatic diamine, care being taken in all of these reactions to provide a large quantity'of-diluent for the reactions in order to favor the formation of macrocyclic compounds. In general, it has been 'found that the concentration of the reactants should not be greater than about 0.02 molar to obtain optimum results.

Another group of macrocyclic compounds useful in practicing our invention include those represented by the *following general formula:

(1) omomoomomoomos,

oHzonz'oomoHro'omom 1,1 O'-dithia-4,7,13,16-tetraoxacyclooctadecane CHzCHzOCHgCHg CHzCHzOCHzCHz 1,7 -dithia-4,l-dioxacyclododecane /'CH2OH2OH2OCH2C'H2CH2 Ha Ha 1,7-dithia-4,10-dioxa-S,5,9,1l-tetramethylcyclododeeane CH CHzO G O CHQCHZ S S 1,9-dithia-4,6,l2,l4r-tetraoxa-5,13-dtoxocyclohexadecane 1,10-dithia-4fl-dioxa-l3,17-dioxoilet,16-d1azacyclononadecane -1,10-dithia-4;7-dioxa-1-2,1 6-dioxo 13,IS-diazacycloheptadecarie onionzo'onzonz'o omen;

s s omorrn mnonzonmn onion,

1,10-dithia4,7-dioxa-13,18-dioX0-14,17diazacycloicosane 1,4-dithia 2-hydroxymethyI-7,1l-dioxo-8,IO-diazacyclotridecane CHZCHZOCHZCEQ CH CH O 0H2 1-thia4,7,10-trioxacyc1ododecane (l2) CHQCHZOCHZCHZ'O CHZCHZOCHZCHQ S S CHZCHZO CHZCHQO CHZCHZO 01120112 1,13-dithia-4,7,l0,16,19,22-hexaoxacyclotetracosane '1,B dithia-3,4-diaza 9,12,i5-trioxa-2,4-cycloheptafdecadiene- -2,5-sulfide (endo) 5,7-diazasl4r,1'T-dioxal,8,13,18-tetra0xo-1,11- dithiacyclononadecane 57,13,16-tetraoxa-3,8,12,17-tetraoxo-1,101dithlacyclooctadecane 7 7 EXAMPLE A.-COMPOUND 1 A reaction mixture composed of 18.7 g. of 1,2-bis(2- chloroethoxy)ethane, 24.0 g. of sodium sulfide nonahydrate, 50 ml. of ethyl alcohol and 50 ml. of water was refluxed on the steam bath overnight and the solvents were then removed by distillation in vacuum. Extraction of the residue with hot absolute ethanol removed the cyclic material which was then recovered from the ethyl alcohol by evaporation and crystallization to give crystals. M.P. 90-92 C.

Analysis.-Calculated (for C H S O C, 48.6; H, 8.1; S, 21.6. Found: C, 47.7; H, 7.8; S, 20.9. Similar data (found) on a larger run was as follows: C, 49.0; H, 8.4; S, 21.8. Calculated molecular weight: 296. Molecular weight found (average of six determinations): 295.

The same reaction may be run in a higher state of dilution, for example, in 400 ml. of ethyl alcohol and 400 ml. of water. Such dilute conditions favor the intramolecular reactions leading to cyclic compounds.

Compound 2 above was prepared in exactly the manner illustrated in Example A by replacing the substituted ethane compound of that example by a molecularly equivalent amount of his (2-chloroethyl)ether.

Compound 3 was prepared in like manner by replacing the substituted ethane compound of Example A by a molecularly equivalent amount of bis(3-chloro-n-propyl) ether.

Compound 4 was prepared in like manner by replacing the substituted ethane compound of Example A by a molecularly equivalent amount of bis(2-chloroisopropyl) ether.

In like manner, Compound 5 was prepared according to the method of Example A above by replacing the substituted ethane compound of that example by a molecularly equivalent amount of bis(2-chloroethyl)carbonate.

The following example illustrates an alternate method for making Compound 2 above.

EXAMPLE B.COMPOUND 2 A reaction mixture composed of 14.3 g. of bis(2-chloroethy1)ether, 13.8 of bis(2-mercaptoethyl)ether, 10.6 g. of sodium carbonate, .3000 ml. of ethyl alcohol, and 3000 ml. of water was refluxed on a steam bath for 63 hours, and the solvents were then removed by distillation in vacuum. Extraction of the residue with hot ethyl acetate removed the organic product which was then recovered from the ethyl acetate by evaporation and distillation in vacuum to give a colorless oil, B.P. 118 C./1 mm. The calculated analysis for the above product, C H O S is as follows: C, 46.1; H, 7.7; S, 30.8; mol. wt. 208. The analysis found was: C, 45.2; H, 7.7; S, 30.3; mol wt. 218.

Another method for preparing Compound 1 above is as follows: 1,2-bis(2-chloroethoxy)ethane, 4.7 g. (0.025 mole), and 1,2-bis(2-mercaptoethoxy)ethane, 4.6 g. (0.025 mole), were dissolved in a solution of 2.6 g. (0.025 mole) of anhydrous sodium carbonate in 1 liter of 50% aqueous ethanol. The reaction mixture was refluxed for 64 hours and the solvent was removed under vacuum. The residue was extracted with 35 ml. portions of boiling ethyl acetate and an equal volume of ethanol was added to the combined extracts. On slow evaporation, 2.5 g. (33.8%) of white crystals, M.P. 9294 C. were obtained. Analyses calculated for C H S O C, 48.6; H, 8.1; S, 21.8. Found: C, 48.6; H, 7.6; S, 21.8. The melting point and infrared absorption spectrum of this compound were identical with that obtained by the reaction of sodium sulfide and 1,2-bis(2-chloroethoxy)ethane.

hydroxide drops) containing absolute ethanol. The

concentration of reactants was 0.002 molar. The desired "8 product was found to have a molecular weight of 410 by boiling point elevation.

This compound was also prepared by reacting 1,2-bis(2- mercaptoethoxy)ethane with N,N'-methylene bis(B-propionamide) at a dilution of 0.00025 molar. A mixed melting point determination of this material with that obtained immediately above showed no depression. The melting point was 197-199 C.

EXAMPLE D .COMPOUND 7 N,N'-methylene bis chloroacetamide was prepared (Ann., vol. 343, page 282) and 1.9 g. (0.01 mole) were dissolved in 4 liters of 50% ethanol containing 1.1 g. of Na CO To this solution were added 1.82 g. (0.01 mole) of 1,2-bis(2-mercaptoethoxy)ethane, and the mixture was heated under reflux for 48 hours. The solvent was removed and the residue was recrystallized twice from ethanol to give 2.4 g. (78%) of material melting sharply at 2092l0 C.

Analysis.Calcd: C, 42.9; H, 6.5; N, 9.1; S, 20.8; mol. wt., 308. Found: C, 42.9; H, 6.5; N, 9.0; S, 21.4; mol. wt., 317.

EXAMPLE B.COMPOUND 8 The reaction of acrylamide with bis(2-mercaptoethyl)- ether followed by reaction with formaldehyde. A mixture of 6.9 g. (0.05 mole) of bis(2-mercaptoethyl)ether and 7.1 g. (0.10 mole) of acrylamide in 500 ml. of absolute ethanol containing 10 drops of benzyl trimethyl ammonium hydroxide solution (30% in methanol) was heated under reflux for two hours, and upon cooling the white precipitate of 3,9-dithia-6-oxa-Lll-undecane dicarboxamide, was filtered ofl and washed with ethanol.

Analysis.-Calcd: C, 42.8; H, 7.1; N, 10.0; S, 22.8. Found: C, 42.8; H, 7.1; N, 10.0; S, 23.1.

5.6 g. (0.02 mole) of this material were mixed with 13.6 ml. of concentrated hydrochloric acid, 1.6 g. of a 35 aqueous solution of formaldehyde (0.02 mole) and 23 ml. of water. The reaction mixture was warmed to 55 C. and after 1 hour, the product was filtered off and washed with cold water.

Analysis.-Calcd: C, 45.2; H, 6.7; N, 9.6; S, 21.9. Found: C, 45.0; H, 6.3; N, 8.3; S, 21.0.

EXAMPLE F.COMPOUND 9 ,fi-Chloropropionyl chloride, 25.4 g. (0.2 mole), was dissolved in 50 ml. of dry diethyl ether and placed in a flask equipped with a stirrer, reflux condenser and dropping funnel. The flask was cooled in an ice bath, and with rapid stirring 6.0 g. (0.1 mole) of ethylenediamine were added dropwise over a 30-minute period. The reaction mixture was then left overnight at room temperature, and a white precipitate was filtered oil and recrystallized from ethanol.

When 0.02 mole each of 1,2-bis(2-mercaptoethoxy)eth ane, the bis-B-chloropropionamide and sodium carbonate were refluxed in 2 liters of 50% ethanol for 5 days, a product melting at 200 C. was obtained. Analysis found: C, 47.8; H, 7.7; N, 8.4; S, 17.7. Calculated for O CHgOGHzCHg-SCHzCHgC NEE-CH2 NHCH2 OH2OCH2CH2-SCH2OH2O A ZO-membered ring, C, 48.0; H, 7.42; N, 8.0; S, 18.3.

EXAMPLE G.COMPOUND 10 Methylene bis acrylamide, 6.28 g. (0.04 mole), and 2,3-dimercapto-1-propanol, 4.32 g. (0.04 mole), were dissolved in 1600 ml. of ethyl alcohol and 10 drops of a 35% solution in methanol of benzyl trimethyl ammonium hydroxide were added as a catalyst. The reaction mixture was heated under reflux for 72 hours. The solvent was partially removed and precipitate A was filtered olf. Upon removal of the remainder of the solvent, a residue, B, was found. Both A and B were recrystallized from ethanol. A-M.P. l93-l98 C. BM.P. 214215 C. '5

Analysis.Calcd: C, 42.9; 'H, 6.8; N, 10.2; S, 22.9. AFound: C, 43.0; H, 6.1; N, 9.7; S, 22.7. BFound: C, 43.9; H, 6.9; N, 11.6; S, 22.7.

Only fraction B was the desired compound, as confirmed by molecular weight determinations.

EXAMPLE H.COMPOUND 11 A reaction mixture composed of 32.0 g. of bis 2-(2- bromoethoxy)ethyl ether, 24.0 g. of sodium sulfide nonahydrate, 2000 ml. of ethyl alcohol and 2000 ml. of water 315 was refluxed on a steam bath for 41 hours, and the solvents were then removed by distillation in vacuum. Extraction of the residue with hot ethyl acetate removed the organic product which was then recovered from the ethyl acetate by-evaporation and distillation in vacuum to give a clear colorless oil. B.P. 90-95 C./1 mm. The calculated analysis for the above product, C H O S, is as follows: C, 50.0; H, 8.3; S, 16.7; mol. wt. 192. The analysis found was: C, 50.4; H, 8.1; S, 16.3; mol. wt. 22.4.

*bromoethoxy)ethyl ether, 50.2 g. of bis 2-(2-mercaptoethoxy)ethyl ether, 23.6 g. of sodium carbonate, 5000 ml. of ethyl alcohol, and 5000 ml. of water was refluxed on a steam bath for 71 hours, and the solvents were then removed by distillation in vacuum. Extraction of the residue with hot ethyl acetate removed the organic product which was then recovered from the ethyl acetate by evaporation and distillation in vacuum to give an amber oil. B.P. 220 C. in a molecular still at a pressure of 10 microns or less. The calculated analysis for the above product, C H O S is as follows: C, 50.0; H, 8.3; S, 16.7; mol. wt. 384. The analysis found was: C, 50.2; H, 8.7; S, 16.3;mol. Wt. 352.

EXAMPLE J.-COMPOUND 13 ll HS-O 2,S-dimercapto-1,3,4-thiadiazole, 4.5 g. (0.03 mole), dissolved in 220 ml. of ethanol and 1,11-dibromo-3,6,9- trioxaundecane, 9.6 g. (0.03 mole), in 220 ml. of ethanol were added dropwise over a 90-minute period to a refluxing solution of 3.2 g. (0.03 mole) of sodium carbonate in 3000 ml. of ethanol and 600 ml. of water. The reaction mixture was refluxed for 15 minutes after the addition'was completed and then left at room temperature overnight. After removal of the solvent and recrystallization of the residue from ethanol, 1.5 g. of crystalline material were obtained, M.P. 84-86 C.

Analysis.Calcd: C, 39.0; H, 5.2; S, 31.2; mol. wt. 308. Found: C, 38.9; H, 5.4; S, 31.6; mol. wt. 309.

EXAMPLE K.-COMPOUND 14 Glycol dimercaptoacetate, 21.0 g. (0.1 mole), and .N,N'-methylene bis acrylamide, 15.4 g. (0.1 mole), were dissolved in 2 liters of ethyl alcohol and added dropwise 0 bath for 7 hours.

over a period of 7 hours to a refluxing solution of 20 drops of 35% methanol solution of benzyl trimethyl ammonium hydroxide in 1 liter of ethanol. After the addition was completed, the reaction mixture was refluxed overnight and then allowed to cool. The crude S, 17.4; N, 7.8; mol. wt. 373.

EXAMPLE L.COMPOUND 15 II II II II HS 01120-0 omorno C-CI-I SH+BrCH20-O 011201120 CCH Br- Solutions of 4.2 g. (0.02 mole) of glycol dimercaptoacetate and 6.08 g.(0.02 mole) of glycol dibromoacetate each in 500 ml. of absolute ethanol were added dropwise from separate dropping funnels to a stirred solution of 2.2 g. (0.04 mole.) of sodium methoxide in 500 ml. of absolute ethanol. Following addition of the reactants, the resulting solution was allowed to stand at room temperature overnight, after which it was refluxed on a steam The product was recovered by evaporation of the ethanol in vacuum on a steam bath, extraction of the residue with ethyl acetate, precipitation by addition of petroleum ether, and recrystallization of the solid from a mixture of ethyl acetate and ethanol.

5 M.P.150.5151.5 C.

Analysis.Calcd for C H O S C, 40.9; H, 40.9; H, 4.6; S, 18.2; mol. wt., 352. Found: C, 41.2; H, 4.6; S, 17.8; mol. wt., 364.

The macrocyclic compounds of our invention can be added to ordinary photographic silver halide emulsions for the purpose of increasing the sensitivity thereof. These macrocyclic compounds are conveniently added to the emulsions in the form of their solutions -or dispersions in organic solvents or organic solvents diluted with water.

The preparation of photographic silver halide emulsions involves three separate operations: (1) emulsification and digestion of silver halide, (2) the freeing of the emulsion of excess water-soluble salts, usually by washing with water, and (3) the second digestion or after-ripening to obtain increased emulsion speed or sensitivity. (Mees, The Theory of the Photographic Process, 1954). The sensitizers of our invention can be added to the emulsion before the final digestion or after-ripening, or they can be added immediately prior to the coating. Our new photographic sensitizers require no special final digestion or after-ripening.

The particular quantity of macrocyclic compound used in a given emulsion can vary, depending upon the effects desired, degree of ripening, silver content of the emulsion, etc. The amount 'used is also dependent upon the particular stage at which the sensitizer is added during the preparation of the emulsion. We have found that from about 50 mg. to about 5 g. of macrocyclic compounds per mole of silver halide is quite adequate to accomplish the desired sensitization of many of the common photographic silver halide emulsions.

.The sensitizers of our invention can be added to photographic emulsions using any of the well-known techniques in emulsion making. For example, the sensitizers can be dissolved in a suitable solvent and added to the silver halide emulsion, or they can be added to the emulsion in the form of a dispersion similar to the technique used to incorporate certain types of color-forming compounds (couplers) in a photographic emulsion. Techniques of this type are described in Jelley et al. US. Patent 2,322,- 027, issued June 15, 1943, and Fierke et al. US. Patent 2,801,171, issued July 30, 1957. As indicated above, the solvent should be selected so that it has no harmful efiect upon the emulsion, and generally solvents or dlluents which are miscible with water are to be preferred. Water or diute alkali is a dispersing medium for some of the sensitizers of the invention. In a preferred embodiment, the sensitizer can be dissolved in solvents, such as ethanol, acetone, pyridine, N,N-dimet'nylformamide, etc., and added to the emulsion in this form. If desired, certain of the sensitizers can be prepared in finely-divided form and dispersed in water alone, or in the presence of a suitable dispersing agent (such as alkali metal salts of aromatic or aliphatic sulfonic acids) and added to the emulsion in this form. It is quite apparent that the sensitizers of our invention should have sufiicient water-dispersibility so that they can be adsorbed to the grains of the silver halide present in the emulsion in sufficient amount to sensitize the emulsion. It is apparent that the optimum amount for each of the sensitizers will vary somewhat from emulsion to emulsion and from sensitizer to sensitizer. The optimum amount for any given sensitizer can be determined for any particular emulsion by running a series of tests in which the quantity of sensitizer is varied over a given range. Exposure of the treated emulsion in conventional photographic testing apparatus, such as an intensity scale sensitometer, will reveal the most advantageous concentrations for that sensitizer in that particular emulsion. Such matters are well understood by those skilled in the art.

The photographic emulsions used in practicing our invention are, of course, of the developing-out type.

The emulsions can be chemically sensitized by any of the accepted procedures. The emulsions can be digested with naturally active gelatin, or sulfur compounds can be added such as those described in Sheppard US. Patent 1,574,944, issued March 2, 1926, Sheppard et al. US. Patent 1,623,499, issued April 5, 1927, and Sheppard and Brigham US. Patent 2,410,689, issued November 5, 1946.

The emulsions can also be treated with salts of the noble metals such as ruthenium, rhodium, palladium, iridium, and platinum. Representative compounds are ammonium chloropalladate, potassium chloroplatinate, and sodium chloropalladite, which are used for sensitizing in amounts below that which produces any substantial fog inhibition, as described in Smith and Trivelli US. Patent 2,448,060, issued August 31, 1948, and as antifoggants in higher amounts, as described in Trivelli and Smith US. Patents 2,566,245, issued August 28, 1951, and 2,566,263, issued August 28, 1951.

The emulsions can also be chemically sensitized with gold salts as described in Waller et al. US. Patent 2,399,- 083, issued April 23, 1946, or stabilized with gold salts as described in Damschroder US. Patent 2,597,856, issued May 27, 1952, and Yutzy and Leermakers US. Patent 2,597,915, issued May 27, 1952. Suitable compounds are potassium chloroaurite, potassium aurithiocyanate, potassium chloroaurate, auric trichloride and 2-aurosulfobenzothiazole methochloride.

The emulsions can also be chemically sensitized with reducing agents such as stannous salts (Carroll US. Patent 2,487,850, issued November 15, 1949, polyamines, such as diethyltriamine (Lowe and Jones US. Patent 2,518,698, issued August 15, 1950), polyamines, such as spermine (Lowe and Allen US. Patent 2,521,925, issued September 12, 1950), or bis([3-aminoethyl) sulfide and its water-soluble salts (Lowe and Jones US. Patent 2,521,- 926, issued September 12, 1950).

The emulsions can also be optically sensitized with cyanine and merocyanine dyes, such as those described in Brooker US. Patents 1,846,301, issued February 23, 1932; 1,846,302, issued February 23, 1932; and 1,942,854, issued January 9, 1934; White US. Patent 1,990,507, issued February 12, 1935; Brooker and White US. Patents 2,112,-

140, issued March 22, 1938; 2,165,338, issued July 11, 1939; 2,493,747, issued January 10, 1950, and 2,739,964, issued March 27, 1956; Brooker and Keyes US. Patent 2,493,748, issued January 10, 1950; Sprague US. Patents 2,503,776, issued April 11, 1950, and 2,519,001, issued August 15, 1950; Heseltine and Brooker US. Patent 2,666,761, issued January 19, 1954; Heseltine US. Patent 2,734, 900, issued February 14, 1956; Van Lare US. Patent 2,739,149, issued March 20, 1956; and Kodak Limited British Patent 450,958, accepted July 15, 1936.

The emulsions can also be stabilized with the mercury compounds of Allen, Byers, and Murray US. Patent 2,728,663, issued December 27, 1955; Carroll and Murray US. Patent 2,728,664, issued December 27, 1955; and Leubner and Murray US. Patent 2,728,665, issued Decrnber 27, 1955; the triazoles of l-leimbach and Kelly US. Patent 2,444,608, issued July 6, 1948; the azaindenes of Heimbach and Kelly US. Patents 2,444,605 and 2,444,- 606, issued July 6, 1948; Heimbac'n US. Patents 2,444,- 607, issued July 6, 1948, and 2,450,397, issued September 28, 1948; Heimbach and Clark US. Patent 2,444,609, issued July 6, 1948; Allen and Reynolds US. Patents 2,713,541, issued July 19, 1955 and 2,743,181, issued April 24, 1956; Carroll and Beach US. Patent 2,716,062, issued August 23, 1955; Allen and Beilfuss U.S. Patent 2,735,769, issued February 21, 1956; Reynolds and Sagal US. Patent 2,756,147, issued July 24, 1956; Allen and Sagura US. Patent 2,772,164, issued November 27, 1956, and those disclosed in Birr in Z. Wiss. Phot., vol. 47, 1952, pages 2-28; the disulfides of Kodak Belgian Patent 569,317, issued July 31, 1958; the quaternary benzothiazolium compounds of Brooker and Staud US. Patent 2,131,038, issued September 27, 1938, or Allen and Wilson US. Patent 2,694,716, issued November 16, 1954 (e.g., decamethylene bis benzothiazolium perchlorate); and the zinc and cadmium salts of Jones US. patent application Serial No. 493,047, filed March 8, 1955 (now US. Patent 2,839,405, issued June 17, 1958).

The emulsions may also contain speed-increasing compounds of the quaternary ammonium type of Carroll US. Patent 2,271,623, issued February 3, 1942; Carroll and Allen US. Patent 2,288,226, issued June 30, 1942; and Carroll and Spence US. Patent 2,334,864, issued November 23, 1943; and the polyethylene glycol type of Carroll and Beach US. Patent 2,708,162, issued May 10, 1955.

The emulsions may contain a suitable gelatin plasticizer such as glycerin; a dihydroxy alkane such as 1,5-pentane diol as described in Milton and Murray US. application Serial No. 588,951, filed June 4, 1956 (now US. Patent 2,960,404, issued November 15, 1960); an ester of an ethylene bis-glycolic acid such as ethylene bis(methyl glycolate) as described in Milton US. application Serial No. 662,564, filed May 31, 1957 (now US. Patent 2,904,- 434, issued September 15, 1959); bis-(ethoXy diethylene glycol) succinate as described in Gray US. application Serial No. 604,333, filed August 16, 1956 (now US. Patent 2,940,854, issued June 14, 1960), or a polymeric hydrosol as results from the emulsion polymerization of a mixture of an amide of an acid of the acrylic acid series, an acrylic acid ester and a styrene-type compound as described in Tong US. patent application Serial No. 311,319, filed September 24, 1952 (now US. Patent 2,852,386, issued September 16, 1958). The plasticizer may be added to the emulsion before or after the addition of a sensitizing dye, if used.

The emulsions may be hardened with any suitable hardener for gelatin such as formaldehyde; a halogen-substituted aliphatic acid such as mucobromic acid as described in White US. Patent 2,080,019, issued May 11, 1937; a compound having a plurality of acid anhydride groups such as 7,8-diphenylbicyclo(2,2,2)-7-0ctene-2,3,5, 6-tetracarboxylic dianhydride, or a dicarboxylic or a disulfcnic acid chloride such as terephthaloyl chloride or naphthalene-1,5-disulfor1yl chloride as described in Allen 13 and Carroll U.S. Patents 2,725,294 and 2,725,295, both issued November 29, 1955 a cyclic 1,2-diketone such as -cyclopentane-1,2-dione as described in Allen and Byers U.S. Patent 2,725,305, issued November 29, 1955; a

bisester of methane-sulfonic acid such as 1,2-di-(methane- -sulfonoxy)ethane as described in Allen and Laakso U.S.

Patent 2,726,162, issued'December 6, 1955 1,3-dihydroxymethylbenzimidazol-Z-one as described in July, Knott and Pollak U.S. Patent 2,732,316, issued January 24, 1956; a dialdehyde or a sodium bisulfite derivative thereof, the aldehyde groups of which are separated by 23 carbon atoms, such as fi-methyl glutaraldehyde bis-sodium bisulfite as described in Allen and Burness Canadian Patent 588,- 451, issued December 8, 1959; a bisaziridine carboxamide such as trimethylene 'bis(1-aziridine carboxamide) as described in Allen and Webster U.S. patent application Serial No. 599,891, filed 'July 25, 1956 (now U.S. Patent 2,950,197, issued August 23, 1960); or 2,3-dihydroxy dioxane as described in Jeifreys US. patent application Serial No. 624,968, filed November 29, 1956 (now U.S. Patent 2,870,013, issued January 20, 1959).

The emulsions may contain a coating aid such as saponin; a lauryl or oleoyl monoether of polyethylene glycol as described in Knox and Davis US. Patent 2,831,766, issued April 22, 1958; a salt of a sulfated and alkylated polyethylene glycol ether as described in Knox and Davis U.S. Patent 2,719,087, issued September 27, 1955; an acylatedalkyl taurine such as the sodium salt of N-oleoyl- N-methyl taurine as described in Knox, Twardokus and Davis U.S. Patent 2,739,891, issued March 27, 1956; the reaction product of a dianhydride of tetracarboxybutane with an alcohol or an aliphatic amine containing from 8 to 18 carbon atoms which is treated with a base, for example, the sodium salt of the monoester of tetracarboxy butane as described in Knox, Stenberg and Wilson U.S. patent application Serial No. 485,812, filed February 2, 1955 (now U.S. Patent 2,843,487, issued July 1, 1958); a water-soluble maleopim arate or a mixture of a watersoluhle maleopimarate and a substituted glutamate salt as described in Knox and Fowler U.S. Patent 2,823,123, issued February 11, 1958; an alkali metal salt of a substituted amino acid such as disodium N-(carbo-p-tert. octylphenoxypentaethoxy) glutamate as described in Knox and Wilson U.S. patent application Serial No. 600,679, filed July 30, 1956 (now U.S. Patent 3,038,804, issued June 12, 1962); or a sulfosuccinamate such as tetrasodium N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamate or N-lauryl disodium sulfosuccinamate as described in Knox and Stenberg U.S. patent application Serial No. 691,125,, filed October 21, 1957 (now U.S. Patent 2,992,108, issued July 11, 1961).

The addenda which we have described may be used in various kinds of photographic emulsions. In addition to being useful in X-ray and other nonoptically sensitized emulsions they may also be used in orthochromatic, panchromatic, and infrared sensitiveemulsions. They may be added to the emulsion before or after any sensitizing dyes which are used. Various silver salts may be used as the sensitive salt such as silver bromide, silver iodide, silver chloride, or mixed silver halides such as silver chlorobromide or silver bromoiodide. The agents may be used in emulsions intended for color photography, for example, emulsions containing color-forming couplers or emulsions to be developed by solutions containing couplers or other color-generating materials, emulsions of the mixed-packet type, such as described in Godowsky U.S. Patent 2,698,794, issued January 4, 1955; or emulsions of the mixed-grain type, such as described in-Carroll and Hanson U.S. Patent 2,592,243, issued April 8, 1952. These agents can also be used in emulsions which form latent images predominantly on the surface of the silver halide crystal or in emulsions which form latent images predominantly inside the silver halide crystals, such as those described in Davey and Knott U.S. Patent 2,592,250, issued April 8, 1952.

ity to one another.

They may alsobe used in emulsions intended for use in diffusion transfer processes which utilize the undeveloped silver halide in the nonimage areas of the negative to form apositive by dissolving the undeveloped silver halide and precipitating it on a receiving layerin close proximity to the original silver halide emulsion layer. Such processes are described in Rott U.S. Patent 2,352,014, issued June 20, 1955, and Land U.S. Patents 2,584,029, issued January 29, 1952; 2,698,236, issued December 28, 1954; and 2,543,- 181, issued February 27, 1951; and Yackel et a1. U.S. patent applicationSer-ial No. 586,705, filed May 23, 1956 (now U.S. Patent 3,020,155, issued February 6, 1962). They may also be used in color transfer processes which utilize thediffusion transfer of an'image-wise distribution of developer, coupler or dye, from a light-sensitive layer to a secondlayer, While the two layers are in close proxim- Color processes of this type are de scribed in Land U.S. Patents 2,559,643, issued July 10, 1951, and 2,698,798, issued January 4, 1955; Land and Rogers Belgian Patents 554,933 and 554,934, granted August 12, 1957; International Polaroid Belgian Patents 554,212, granted July 16, 1957 and 554,935, granted August 12, 1957; Yutzy U.S. Patent 2,756,142, issued July 24, 6, and Whitmore and Mader U.S. patent application Serial No. 734,141, filed May 9, 1958.

In the preparation of the silver halide dispersions employed for preparing silver halide emulsions, there may be employed as the dispersing agent for the silver halide in its preparation, gelatin or some other colloidal material such as colloidal albumin, a cellulose derivative, or a synthetic resin, for instance, a polyvinyl compound. Some colloids which may be used are polyvinyl alcohol or a hydrolyzed polyvinyl acetate as described in Lowe U.S. Patent 2,286,215, issued June 16, 1942; a far hydrolyzed cellulose ester such as cellulose acetate hydrolyzed to an acetyl content of 1926% as described in U.S. Patent 2,327,808 of Lowe and Clark, issued August 24, 1943; a water-soluble ethanolamine cellulose acetate as described in Yutzy U.S. Patent 2,322,085, issued June 15, 1943; a polyacrylamide having a combined acrylamide content of 30-60% and a specific viscosity of 0.251.5 or an imidized polyacrylamide of like acrylamide content and viscosity as described in Lowe, Minsk and Kenyon U.S. Patent 2,541,474, issued February 13, 1951; zein as described in Lowe U.S.-Patent 2,563,791, issued August 7, 1951; a vinyl alcohol polymer containing urethane carboxylic acid groups of the type described in Unruh and Smith U.S. Patent 2,768,154, issued October 23, 1956; or containing cyano-acetyl groups such as the vinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh, Smith and Priest U.S. Patent 2,808,331, issued October '1, 1957; or a polymeric material which results from polymerizing .a protein or a saturated acylated protein with a monomer having a vinyl group .as described in U.S. application Serial No. 527,872 of Illingsworth, Dann and Gates, filed August 11, 1954 (noW U.S. Patent 2,852,382, issued September 16, 1958).

if desired,-con1patible mixtures of two-or more of these colloids may be employed for dispersing the silver halide in its preparation. Combinations of these antifoggants, sensitizers, hardeners, etc., may be used.

As indicated above, the sensitized emulsions of our invention can be used in the preparation of color photographs. This may be accomplished either by using photographic emulsions containing color-forming compounds or couplers, or by the use of photographic emulsions which are developed in color developers containing color-form ing compounds or couplers. Color-forming compounds or couplers which can be incorporated in photographic silver halide emulsions to provide the useful results of our invention include the couplers listed in Graham and SagalU'S. application Serial No. 779,839, filed December 12, 1958. Typical couplers include the following:

Couplers Producing Cyan Images Nnoo-ou-o- -ouu Couplers Producing Magenta Images etc.

l-p-sec. amylphenyl-3-n-amyl-5-pyrazolone 1-p-laurylphenyl-3-methyl-5-pyrazolone 1-phenyl-3benzoylamino-5-pyrazolone 1 (p phenoxyphenyl) 3 (p tert. amyloxybenzoyl)- amino-S-pyrazolone 1 (2,4,6 trichlorophenyl) 3 phenylacetamido 5- pyrazolone 1 (2,4,6 trichlorophenyl) 3 [3" (2",4' ditert. arnylphenoxy acetamido)benzamido] 5 pyrazolone 1 (2,4,6 trichlorophenyl 3 [,8 2",4'" di tert.

amylphenoxy) -propionamido] -5-pyrazolone 1 (2,4',6 tribromophenyl) 3 [3" (4" tert.

amylphenoxy -benzamido] -5-pyrazolone Couplers Producing Yellow Images N-amyl-p-benzoylacetaminobenzenesulfonate on {3 [on (2,4 di tert. amylphenoxy)butyramido]- benzoyl}-2-methoxyacetanilide a {3 [oz-(2,4 di tert. amylphenoxy)acetamido]- benzoyl}-2-methoxyacetanilide Ethyl-p-benzoylacetaminobenzenesulfonate The above couplers are purely illustrative, and it is to be understood that other couplers can be used to advantage to obtain the useful results of our invention.

As can be seen by reference to the large number of macrocyclic compounds included Within our invention,

as well as the large number 0r color-forming compounds which can be employed in combination therewith, a number of combinations of sensitizing compounds and colorforming compounds are possible. In order to determine quickly the effectiveness of a particular combination, it has been found that the screening technique described by Pontius and Thompson in Phot. Sci. Eng, vol. 1, pages 4-51, can be used to get an idea of the potential effectiveness of a given combination for use in a photographic color element containing a coupler. This technique does not necessitate the preparation of any coupler dispersions, but the sensitizers can be added to ordinary photographic silver halide emulsions of the type used in black-and-White photography, such as gelatino-silverbromiodide emulsions, and the emulsions exposed in an intensity scale sensitometer to daylight quality radiation for a fraction of a second (usually and processed for about 15 minutes in a phenylenediamine color developer, to which has been added 10 g. per liter of H- acid. The pH of this developer is usually adjusted to 10.8 by adding sodium hydroxide. A suitable developer composition for this screening technique is as follows.

4-amino-3-methyl-N-ethyl-N-(B methyl sulfonamidoethyl) aniline sulfate g 8.0 Sodium carbonate monohydrate g 40.0 Sodium bromide g 1.5 Sodium thiocyanate g 0.2 Benzotriazole g .03

Water total to 1 liter, pH 10.8:L-.1.

The following examples will serve to illustrate more fully the manner of sensitizing photographic silver halide emulsions according to our invention, as well as determining whether such emulsions can be usefully employed in the preparation of photographic color images, using the techniques described by Pontius and Thompson, as mentioned above. The data in the column headed DK50 Data were obtained as follows:

An ordinary photographic silver brorniodide emulsion containing a sensitizing dye, a sulfur sensitizer of the type mentioned in Sheppard U.S. Patent 1,623,499, mentioned above, and gold sensitized in the manner indicated in US. Patent 2,448,060, mentioned above, was divided into several portions. Macrocyclic compounds of the type obtained in the above examples were then added in solutions in an organic solvent, such as ethanol or N,N-dimethylformamide, in the amounts indicated in the table. The various portions of emulsions were then coated on a transparent support, such as cellulose acetate and then dried. The dried coatings were then exposed for about sec. to daylight quality radiation in an Eastman Type Ib Sensitometer. The exposed coatings were then developed for about 5 minutes in a photographic developer having the following composition (DK50):

N-methyl-p-aminophenol sulfate 2.5 Hydroquinone 2.5 Sodium sulfite (dry) 30.0 Sodium borate 10.0 Potassium bromide 0.5

Water to make one liter.

The relative speed, as compared with a portion of the emulsion containing no macrocyclic compound, and fog for each of the coatings was then measured.

The data in the following table entitled Color Test were obtained according to the technique of Pontius and Thompson as outlined above.

TABLE I DK-50 Data Color Test Example Addendum (g./mol.

AgX)

Rel. Fog Rel. Fog Speed Speed none 100 12 159 17 Compound 1 (O.3) 148 .16 166 .20 none 100 13 Compound 11 (3.0) 129 .16 none 100 .13 Compound 12 9) 178 16 none 100 .14 Compound 2 123 .14 none 100 .12 Compound 6 (0.9) 132 12 none 100 14 Compound 8 (0.3)"-.- 209 18 100 .14 224 .26 100 .14 151 .20 none 100 .12 Compound 7 (3.0).-." 126 .15 none 100 .13 Compound 14 (3.0)..-- 138 .19 none 100 .13 Compound (0.9)...- 151 .14

The following examples will serve to illustrate the effect produced by the macrocyclic compounds of our invention in photographic silver halide emulsions which contain a coupler or a color-forming compound.

In Table II below, is shown the effect produced by one of our macrocyclic compounds in an ordinary negative speed silver bromiodide emulsion which had been digested to optimum sensitivity with a mixture of a labile sulfur compound of the type shown in Sheppard US. Patent 1,623,499, mentioned above, and a gold compound of the type shown, for example, in US. Patent 2,448,060, mentioned above, and which had been red-sensitized (ca. 600-700 mg) with a spectral sensitizing dye. The emulsion contained a macrocyclic compound in the amount indicated in the table, and also contained a coupler dispersion of one of the color-forming compounds for producing the cyan image upon color development, as identified further below. Two series of coatings were prepared for each of the emulsions, one for processing in a color negative process and another series for processing in a reversal color process. Each of the emulsions was coated on a transparent support, such as cellulose acetate film, dried, and then exposed in an Eastman Type Ib Sensitometer to daylight quality radiation for approximately 4 second. Each was then processed through the color negative process or the reversal color process. A typical negative color process is described in detail by W. T. Hanson, Jr. and W. I. Kisner in an article in the Journal of the Society of Motion Picture and Television Engineers, vol. 61 (1953), pages 667-701. The reversal color process was as follows:

The exposed film was developed in a developer having the following composition:

Sodium hexametaphosphate g 2.0 N-methyl-p-aminophenol sulfate g 6.0 Sodium sulfite, anhydrous g 50.0 Hydroquinone g 6.0 Sodium carbonate monohydrate g 35.0 Potassium bromide g 2.0 Sodium thiocyanate g 1.5

0.5% solution of 6-ni-trobenzimidazole nitrate cc 12.0 0.1% solution of potassium iodide cc 10.0 Water to make 1 liter.

The element was then thoroughly washed with water and treated in a hardening bath having the following composition:

Potassium chrome alum crystals g 30.0 Water to make 1 liter.

The element was then thoroughly washed with water and 18 treated for 30 seconds in a solution having the following composition:

Sodium borohydride g 0.25 Sodium hydroxide g 4.0 Water to make 1 liter.

The element was then treated in a color developer having the following composition:

Benzyl alcohol cc 6.0 Sodium hexametaphosphate g 2.0 Sodium sulfite, anhydrous g 5.0 Trisodiu-m phosphate g 40.0 Potassium bromide g 0.25 0.1% solution of potassium iodide cc 10.0 Sodium hydroxide g 6.5 Color developer 1 g 11.33 Ethylenediamine sulfate g 7.8 Citrazinic acid g 1.5

Water to make 1 liter.

1 4-aminp-N-ethy1-N -(fi methanesulfonamidoethyl)-m-toluidine sesquisulfate monohydrate.

The element was then thoroughly washed with water and treated in a clearing and fixing bath having the following composition:

Sodium thiosulfate g 150.0 Sodium bisulfite g 20.0 Water to make 1 liter.

The element was then treated in a bleach bath having the following composition:

Potassium dichromate g 5.0 Potassium ferricyanide g 70.0 Potassium bromide g 200 Water to make 1 liter.

The element was again washed and treated once again with the clearing and fixing bath identified above. The element was again washed and treated in a stabilizing bath having the following composition:

Formaldehyde (37% by weight) cc 7.0 Dispersing agent g 0.5 Water to make 1 liter.

1 Such as Triton X-100, i.e., an alkylaryl polyether alcohol (octylphenoxy polyethoxy ethanol).

In color coating 1(b) below, the emulsion contained a dispersion of a phenol coupler, e.g., one of the couplers numbered 1 to 6 of Fierke et al. US. Patent 2,801,171 (column 2), in a suitable solvent, such as tri-o-cresyl phosphate, or dibutyl phosphate. In the following table, there is shown the speed increase produced by one of our macrocyclic compounds, as well as the change in D max. in the reversal color process and the change in D min. in the color negative process.

TABLE IL-SINGLE LAYER-C(EIEOR PROCESSED TO CYAN A Rev. Process 0. Neg. Process Color Addendum (gJmol. Coating AgX) ALog AD ALog AD E max. E min.

{(a) none 0 0 0 0 (b) Compound 1 (0.3)-" 15 10 12 +.00

than the other, the faster emulsion being coated over the slower emulsion. Both of the emulsions contained the same ingredients. The emulsions contained a dispersion in tri-o-cresylphosphate of a pyrazolone coupler, e.g., couplers Nos. 7, etc., of Fierke et al. US. Patent 2,801,171 (column 2) and a phenylazopyrazolone coupler, e.g., coupler No. 8 of US Patent 2,801,171. The speed and density for each of the coatings is shown in the following table after the coatings were exposed in an Eastman Type Ib Sensitometer to daylight quality radiation and after processing in the color negative process or the reversal color process.

TABLE III.-SINGLE LAYER-COLOR PROCESSED TO MAGENTA IMAGE While Tables II and III above illustrate the effects of our macrocyclic compounds as applied to single layers of a multi-layer photographic element, it is apparent that these advantages apply to the entire multi-layer material which contains one of our macrocyclic compounds in at least one of the differentially-sensitized layers.

It has also been found that the macrocyclic compounds of our invention can be added to photographic developers, which may or may not contain color-forming compounds, in order to increase the effective speed of photographic emulsions which have not been previously sensitized by incorporation of one of the macrocyclic compounds of our invention. This discovery has been found to apply to the number of photographic silver halide emulsions, including emulsions containing color-forming compounds or couplers, as well as photographic silver halide emulsions containing no such color-forming compounds. The latter emulsions can be used in black-and-white photography, or alternatively, they can be used in a photographic, color process wherein the color-forming components are incorporated in the color developers.

It has also been found that photographic silver halide emulsions can be sensitized with macrocyclic compounds similar to those illustrated above, wherein the sulfur atoms of the macrocyclic ring are replaced by oxygen atoms. For example, two molecules of ethylenediamine can be condensed with two molecules of methylmethacrylate at a temperature of about 3040 C., over a period of about 65 minutes to provide 1,5,8,12-tetraza-3,lO-dimethyl-2,9-cyclotetradecanedione. This compound was particularly effective in photographic emulsions intended for color photography and produced a speed increase of 100% in such emulsions. Similar compounds can be prepared by replacing the ethylenediamine with other aliphatic or aromatic primary diarnines, including diethylenetriamine, cystine, djenkolic acid, 1,3-diamino-2-propanol, etc. It has been found, in general, that these oxygen analogues do not provide sensitizing properties comparable to those provided by the sulfur compounds of the present invention.

Macrocyclic compounds of the classes represented by Formulas I, Ia and IV containing less than 12 atoms in the ring (e.g., 8 to 11 atoms) can also be added to photographic silver halide emulsions to alter the sensitivity thereof, although macrocyclic compounds as hereinafter claimed have been found to be especially useful.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

What We claim as our invention and desire secured by Letters Patent of the United States is:

1. A photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the folowing general formula:

wherein R and R each represents a member selected from the class consisting of alkylene and alkylene-W- alkylene, wherein w represents a member selected from the class consisting of an oxygent atom, a sulfur atom, a carboxylic ester radical, a carbonic ester radical and a carboxylic amide radical, and Q represents a member selected from the class consisting of an oxygen atom and a sulfur atom, said marcocylic compound containing at least 12 atoms in a monocyclic, macrocyclic ring, and containing at least one atom selected from the class consisting of an oxygen atom and a nitrogen atom in said monocyclic, macrocyclic ring, said monocyclic, macrocyclic ring consisting of from 8 to 16 carbon atoms, from 1 to 4 sulfur atoms, from 0 to 6 oxygen atoms and from 0 to 4 nitrogen atoms.

2. A photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general wherein R and R" each represents alkylene containing from 2 to 4 carbon atoms, Q represents a member selected from the class consisting of a sulfur atom and an oxygen atom, and m and n each represents a positive integer of from 1 to 3, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring.

3. A photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general formula:

wherein R represents alkylene containing from 1 to 3 carbon atoms, X represents a member selected from the class consisting of (1) alkylene containing from 2 to 4 carbon atoms, and (2) alkylene-w-alkylene, wherein W represents a member selected from the class consisting of an oxygen atom and a sulfur atom, and (3) a group wherein R represents a member selected from the class consisting of a hydrogen atom, a hydroxyl group, a sulfo group, a carboxyl group and an amino group, and Y represents a member selected from the class consisting of alkylene containing from 1 to 4 carbon atoms and alkylene-w-alkylene, wherein w represents a member selected from the class consisting of an oxygen atom, and a sulfur atom, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring.

4. A photographic silver halide emulsion which has been sensitized with a labile sulfur compound and a gold salt, said photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected 21 from the class represented by the following general formual:

wherein R and R each represents a member selected from the class consisting of alkylene and alkylene-walkylene, wherein w represents a member selected from the class consisting of an oxygen atom, a sulfur atom, a carboxylic ester radical, a carbonic ester radical and a carboxylic amide radical, and Q represents a member selected from the class consisting of an oxygen atom and a sulfur atom, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring, and containing at least one atom selected from the class consisting of an oxygen atom and a nitrogen atom in said monocyclic, macrocyclic ring, said monocyclic, macrocyclic ring consisting of from 8 to 16 carbon atoms, from 1 to 4 sulfur atoms, from to 6 oxygen atoms and from 0 to 4 nitrogen atoms.

5. A photographic silver halide emulsion which has been sensitized with a labile sulfur compound and a gold compound, said photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general formula:

wherein R and R" each represents alkylene containing from 2 to 4 carbon atoms, Q represents a member selected from the class consisting of a sulfur atom and an oxygen atom, and m and n each represents a positive integer of from 1 to 3, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring.

6. A photographic silver halide emulsion containing a sensitizing amount of a labile sulfur compound and a gold salt, said photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general formula:

wherein R represents alkylene containing from 1 to 3 carbon atoms, X represents a member selected from the class consisting of (1) alkylene containing from 2 to 4 carbon atoms, (2) alkylene-w-alkylene, wherein W represents a member selected from the class consisting of an oxygen atom and a sulfur atom, and (3) a group wherein R represents a member selected from the class consisting of a hydrogen atom, a hydroxyl group, a sulfo group, a carboxyl group and an amino group, and Y represents a member selected from the class consisting of alkylene containing from 1 to 4 carbon atoms and alkylene-w-alkylene, wherein w represents a member selected from the class consisting of an oxygen atom, and a sulfur atom, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring.

7' A photographic silver halide emulsion containing a sensitizing amount of the macrocyclic compound represented by the following formula:

CHzCHzOCHzOHzOCHzCE: s s

CH2GHzOCH OH OCHzOH 8. A photographic silver halide emulsion containing a sensitizing amount of the macrocyclic compound represented by the following formula:

9. A photographic silver halide emulsion containing a sensitizing amount of the macrocyclic compound represented by the following formula:

10. A photographic silver halide emulsion containing a sensitizing amount of the macrocyclic compound represented by the following formula:

11. A photographic silver halide emulsion containing a color-forming compound capable of coupling with the oxidation products of a color developer containing a color developing agent containing at least one primary aminoaryl group to produce a colored compound, said emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general formula:

wherein R and R each represents a member selected from the class consisting of a alkylene and alkylene-walkylene, wherein w represents a member selected from the class consisting of an oxygen atom, a sulfur atom, a carboxylic ester radical, a carbonic ester radical and a carboxylic amide radical, and Q represents a member selected from the class consisting of an oxygen atom and a sulfur atom, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring, and containing at least one atom selected from the class consisting of an oxygen atom and a nitrogen atom in said monocyclic, macrocyclic ring, said monocyclic, macrocyclic ring consisting of from 8 to 16 carbon atoms, from 1 to 4 sulfur atoms, from O to 6 oxygen atoms and from 0 to 4 nitrogen atoms.

12. A method for producing a photographic image comprising developing an exposed photographic silver halide emulsion in the presence of a macrocyclic compound selected from the class represented by the following general formula:

wherein R and R each represents a member selected from the class consisting of alkylene and alkylene-w-alkylene, wherein w represents a member selected from the class consisting of an oxygent atom, a sulfur atom, a carboxylic ester radical, a carbonic ester radical and a carboxylic amide radical, and Q represents a member selected from the class consisting of an oxygen atom and a sulfur atom, said macrocyclic compound containing at least 12 atoms in a monocyclic, macrocyclic ring, and containing at least one atom selected from the class consisting of an oxygen atom and a nitrogen atom in said monocyclic, macrocyclic ring, said monocyclic, macrocyclic ring consisting of from 8 to 16 carbon atoms, from 1 to 4 sulfur atoms, from to 6 oxygen atoms and from 0 to 4 nitrogen atoms.

13. A photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general formula:

Rgi loRsoi lRz carbon atoms and R represents alkylene containing from 2 to 4 carbon atoms.

24 14. A photographic silver halide emulsion containing a sensitizing amount of a labile sulfur compound and a gold compound, said photographic silver halide emulsion containing a sensitizing amount of a macrocyclic compound selected from the class represented by the following general formula:

ll ll R200 R CR2 wherein R represents alkylene containing from 1 to 3 carbon atoms and R represents alkylene containing from 2 to 4 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS Brooker et a1 Sept. 27, 1938 Yutzy et a1. May 27, 1952 Beavers et al. June 14, 1960 

12. A METHOD FOR PRODUCING A PHOTOGRAPHIC IMAGE COMPRISING DEVELOPING AN EXPOSED PHOTOGRAPHIC SILVER HALIDE EMULSION IN THE PRESENCE OF A MACROCYCLIC COMPOUND SELECTED FROM THE CLASS REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 